Metal-stretching press having slidable platen supports provided with clamping faces



March 2, R. J. LINDSEY METALSTRETCHING PRESS HAVING SLIDABLE .PLATEN SUPPORTS PROVIDED WITH CLAMPING FACES 7 Filed Dec. 8, 1944 3 Sheets-Sheet l Fig.5

INVENTOR 4 ROBERT J. LINDSEY 3% ZJJQQ ATTORNEY March 2, 1948. R J. LINDSEY 2,437,105

METAL STRETCHING PRESS HAVING SLIDABLE PLATEN SUPPORTS PROVIDED WITH CLAMPING FACES Filed Dec. 8, 1944 3 Sheets-Sheet 2 27s 6 I I INVE'NTOR ROBERT J. LINDSEY ATTORNEYS March 2, l9

48. R. J. LINDSEY METAL STRETCHING PRESS HAVING SLIDABLE PLATEN SUPPORTS .PROVIDED'WITH CLAMPING FACES Filed Dec. 8, 1944 5 Sheets-Sheet 3' .INVENTOR ROBERT J. LINDSEY ATTORNEY Patented Mar. 2, 1948 UNITED METAL-STRETCHING PRESS HAVING SLID- ABLE PLATEN SUPPORTS PROVIDED WITH CLAIWPING FACES Robert J. Lindsey, Mount Gilead, Ohio, assignor to H-P-M Development Corporation, Wilmington, DeL, a corporation of Delaware Application December 8, 1944, Serial No. 567,159

13 Claims. 4 (01. 153-48) This invention relates to presses particularly of the type forming metal sheets by stretching them over a die member.

One object is to provide a mechanism clamping opposite edges of a sheet metal workpiece by a single power means in a single operation.

Another object is to provide a stretching press wherein the workpiece may be given a compound curved surface in a single stretching operation.

A further object is to provide a pivoted press platen that is slightly tiltable so that the die member carried thereby may adjust itself and conform to the contour of an irregularly-shaped workpiece.

A still further object is to provide a structure clamping opposite edges of the workpiece and locking the clamping elements into a rigid unitary structure in a single operation whereby all reactions of the press plungers are taken by the clamping structure itself and are not transmitted to the press frame.

A still further object is to provide a. press clamp having three relatively movable members together with double acting power means to close said members into gripping relation with opposite side edges of a work sheet by one direction of motion of said power means; and to positively open or separate said members to fully release the work sheet by a single reverse operation of said power means.

A still further object is to provide a stretching press that is easily and simply constructed, positive in operation and that is well adapted for automatic control efiecting operations of clamping, stretching'and release, in sequence.

Other objects and advantages will become ap--,

through the press taken'on the line 3-3 of Figure 1; I

Figure-'4 is a transverse section through the platen of the press taken on the line 4-4, Figure 2;

Figure 5 is a perspective view showing one type of jaw facing adapted foruse on the jaw members; v

Figure 6 is a plan view of a press in which the jaw members have been replaced with jaw members having curved gripping surfaces.

Figure 7 is a view similar to Figure 3 but show ing a sheet of metal in the press clamped between the jaw faces and prior to energization'of the platen rams; and

Figure 8 is a view similar to Figure 7 but showing the platen actuated to drive the die carried thereon into stretching position.

Referring in detail to the drawings wherein like numerals identify corresponding parts throughout, IIl indicates the generally rectangular frame formed with parallel side tracks I8 and a portion indicated at I2, Figure 3, upstanding above the upper level of tracks I8 and shouldered to receive a fixed jaw member I4 having a knurled or roughened gripping facing I6. At its end opposite member I4, frame I0 is formed with a supporting surface Illa, somewhat below the upper level of tracks iii. A number of cylinders II, Ila and Ill), are rigidly secured in any desired manner to supporting surface Illa. As shown at Figure'l, three cylinders are employed, and central cylinder II is double acting, while cylinders Ila and III; are single acting. It will be understood, however, that the invention is not limited to any particular number of cylinders and that, within physical limits, any number may be employed. In some cases, one cylinder alone will suffice.

Cylinders II, Ila and Nb are located with their axes parallel to the path determined by tracks [8 and, preferably, closely adjacent a horizontal plane centrally through jaw member Plungers or rods I5, I5a and I5!) extend within the respective cylinders through glands I1, I10 and Nb, and from Figures 1 and 3 it will be noted that plunger I5 is made double acting by a piston l9 attachedthereto, and fluid connections 20 and 2| admitting and exhausting fluid under pressure to and from said cylinder. Fluid connections 20a and 20b are provided, conveying fluid under pressure to cylinders Ila and Nb, respectively. In practice, all cylinders will be supplied from a common pressure source,

A bar 22 has its ends shaped to be supported and guided by tracks I8 so that it moves substantially in translation only in a direction normal to its length. This bar has a jaw member 23 fixed thereto in any suitable manner and provided with a knurled gripping facing 24. Thus, as fluid under pressure is admitted to cylinders II, Na and III) through connections 20, 20a and 20b, bar 22 .is moved along tracks I8 to the left in, Fig e 1; and

'lugs 32a. tened, as at2'le; to-fit between these lugs, and .apivot pin 34 fits aligned apertures in lugs- 32a pair.

der bores 6. 26a, 26b, 26c and 26d having their" axes normally vertical, and in each of which a respective plunger 21 and 21a to 21d is reciprocably guided by glands 28.. A pressure conduit 29 leads from a source of pressure, not shown, and has branches to each of thebores 25and 26a to 26d, as clearly indicated at Figure 2, whereby all pistons 21 etc., may be forced upwardly. inv

bar 22, lugs 22a and 22b engage collars 52 and operate through rods 50 and 5! to apply a retracting force to member 25, whereby the latter is also moved until pins 44 are clear of holes 43.

he ne ation of he inven ion wi now be clean. Assume Ifor examplefthat it is desired to stretch a piece of sheetr'iietal into a form that is generally U-shaped in cross section but of a form curved about two or more angularlyrelated'axes, .that is, a surface whose generathe line {is'fa curve rather than a straight line.

'A'die'or dies as shown at in Figure 7 having the desired surface contour of the finished aradmitting fluid under. pressure through a passagein-its upper .flatsurface. Centrally of its lower surface, platen 32 isformed with a pair of spaced Theupperend of plunger 27 is flatand flattened portion 21a to pivotally, connect .plunger 21 and platen 32. .Parallel guide strips 40 are fixed to the under sldeof platen 32 to .ex-

tend longitudinally.thereofon either side of lugs -32a. These strips. are rabbeted as indicated at 4011, Figure 4, to form guide channels therebetween. Slides 4|, T-shapedincross-section, have .stem of each slide projects downwardly to flt between the grooved upper ends of the respective plungers 21a to 21d. ,Pivot pins 42 pass through aligned holes in the stems of slides 41 and the grooved ends v.of v.plungers 21a :to 21d,

whereby each slide is pivotally connected toa respective plunger. From.this description, and from inspection of Figure 2, it will be notedthat bar 32 may'have aslight .tilting movement about the axis of pin 34 to thereby conform to the .par-

ticular shape of the dieor dies intendedto be mounted on bar 32 and secured thereto by T-slots 33.

-Member hasformedtherein two seriesof -holes 43, flared at their outerends', and so positioned as to receive corresponding series of .dowel pins 44 and 45 fixed in frame In and bar 22, re-

spectively, as shown at Figure '3. Member 25 is and it Will be noted'that face-plates l6 and 48 are aligned and form a coacting pair of gripping surfaces while plates 24 "andi49 form a second Bar 22 has lugs 22a, 22b extending therefrom as shown at Figure 1 while'memb'er .25 has corresponding lugs 22c and-22d.- Rods 50, 5| slidably pass through aligned holes in the respec- "tive pairs of lugs and have collarsi'52 fixed thereon to engage the opposite faces of. the lugs. The

spacing of collars 52 is so Jadjusted. that, .at' a desired position in the retraction movement of their heads slidablyfitting these channels and. the

itic l e' is ls'ecriifedtoi pressure bar 32 by means of slots 63. The .ork piece, indicated at 12 in Figure 7, bent into the form of a U, is inserted so that one edge "lles'between faces [6 and 48 while the other edge lies between faces 24 and 49. A valve, not shown, is then operated admitting fluid under pressure througfi ccnduits 20, 20a and 201). Bar ZZ'fis"therebylmoveduntilpins 451enter one set 6f holes 43 in member 251' and one edge of the workpiece ,ls clampedfbetweeri ,faces24 and A1; cehtiriiil dimovemnt jofj barjzz then moves member'25 lu'nt'ilpins .44 enter' the other set of holes 43 and the other edge ofthe workpiece is "clamped between faces l6and'48L flfh'e edges of the workpiece are'riow rigidly clamped in the press and, bylreason of pins 44' and 45, the parts 22 and 25 are firmly and rigidly fixed to frame If At this stageof theworking cycle the press parts'and workpiece are infth'eI'pofsition ,illu strated iii'Fi'gure 7. "Fluid underpressure is new admitted to conduit 29 to simultaneously .ur'ge plungers 2l and" 21a to 21d upwardly and thus force'the dies against the concave portion 'of the work fpiecel' to,.thereby' stretch the [work piece and force it .to co'nf'ormto the shape' of dies on bar 32.' At the end of the stretching operation, the press parts and'the workpiece'are in the position illustrated. in FigurefS. After the desired shape has been thus imparted to the workpiece, conduits 2 9,20',2lla and 20b are, connected to exhaust ,while pressure is admitted ,to fconduits 2| .ar'i'd'3l ijt'o thereby lower bar 32, retr'act' bar' 22 from m mber and, through rods '50, elfmo e ember '25 from face 1 6" to the position shownl ,jat'fEi gur 1.

' 'While, for "simplicity'of illustration, 1 have shown the clamping faces lQS'ffiB, 49'an'd '24'as I p of Figure 16 Ihave'shojwn my invention'as adaptedfto operate upon Jana give "except tne'cmziipmgismqface are Itne sam as in the species tr'r'igures'r to 3, nd h ce :have been given corresponding rj erence"c .The pl ten 6r pressu e per, i325 and ts attached plungers have been omitted in the interests of clarity. It istherefore merely necessaryto point out thatjaw m'er'nbers 5 3, 54*having complemen- "tary curved races; "are substituted re'rpia'ne jaw :53, 54 31111755,:55' may'zhave the same or difierent contours. The operation of this species ;is the isameas that of 'Figultes-lto 3 and hence ,need not ;be idescribed'inffieta 'l; .L kewise the dies .used may be curved in a vertical planemorrna'l to While I have shown the embodiment of my invention now preferred by me, it is clear that numerous modifications and substitutions of equivalents will occur to those skilled in the art. Therefore I donotwish to be limited to the specific embodiment shown but desire to reserve all such modifications and substitutions as fall within the scopeof the claims.

Having now fully described my invention, what I claim and desire to secure by United States Letters Patent is:

1. In a stretching press, a press block having a plurality of parallel cylinder bores therein, a plunger reciprocable in each bore, a platen, a pivotal connection between one plunger and said platen, a sliding pivotal connection between each remaining plunger and said platen, said block havinggenerally parallel clamp faces along opposite sides thereof in planes substantially parallel to the plane of saidplungers, and a press frame, having track means on which said block is guided for translation substantially normal to said planes.

2. In a stretching press, a press block, a press platen, fluid pressure operated power means between said platen and block, said block having clamp faces on opposite sides thereof substantially parallel tothe direction of movement of said platen, a press frame having means guiding said block in a direction substantially normal to said faces and also having a clamp face engageable with one clamp face of said block, a press bar guided in said direction on said frame and having a clamp face engageable with the other clamp face on said block,-and power means connected to shift said bar and therethrough said block to move all said faces into clampin relation. r

v '3. Astretching press comprising a press frame having straight line guide means and a clamp face substantially normal to said line, a press block movable on saidguide means to bring one of two opposite clamp faces thereon into clamping relation with the face on said frame, a bar movable on said guide means to bring a clamp face thereon into clamping relation with the other clamp face on said block, power means to engage and to move said bar and therethrough said block to clamp opposite edges of a workpiece between the respective pairs of said clamp faces, a platen, and fluid pressure responsive means supporting said platen on said block and operable to move dies on said platen to stretch a workpiece clamped between said faces.

4. A stretching press comprising a press block having a plurality of parallel cylinders, a plunger in each cylinder, a platen, a connection between the external end of each plunger and said platen, said block having a pair of clamp faces on opposite sides thereof, a frame having track means normal to said faces and a clamp face cooperable with one face on said block to form a pair therewith, said block being guided by said track means, a press bar guided by said track means and having a clamp face cooperable with the other clamp face on said block to form a second pair therewith, power means operable to force said pairs of clamp faces into work-clamping relation, and projections on said frame and bar adapted to move in recesses in said block to rigidly unite said frame, block and bar when said faces are in clamping relation.

5. In a stretching press, a cylinder block having clamp surfaces on opposite sides thereof and a plurality of cylinders with parallel bores, a plunger reciprocable in each bore, a platen, a

pivotal connection between each plunger and said platen, a frame supporting and-guiding said block for rectilinear movement thereon and having a clamp surface cooperable with one surface on said block, a bar supported and guided by said frame to move a clamp surface thereoninto clamping relation with the other surface on said block, a plurality of parallel cylinders on said frame, a plunger in each cylinder engageable with said bar to reciprocate said bar and therethrough said block and force said faces into clamping relation, and a lost motion connection between said bar and block operable to retract said block after a predetermined retraction movement of said bar.

6. In a stretching press, a press bed having a.

fixed jaw, a movable jaw translatable on said bed toward and from said fixed jaw, a block. freely slidable on said bed between said fixed and movable jaws and having jaws complementary to said fixed and said movable jaws to form. jaw pairs between which the opposite edges of a sheet may be clamped as said movable jaw forces said block toward said fixed jaw, power means on said bed and operable to translate said movable jaw and therethrough said block, cylinders in said block, a platen, and plungers connected to. said platen and operable by pressure fluid in said cylinders to move a die thereon for stretching action on a sheet clamped between said jaw pairs.

'7. In a stretching press a first clamping element, a second clamping element, a member freely slidable between said elements and having clamping elements coacting with said first and second elements respectively when all elements are moved into clamping relation to grip opposite edges of a generally U-shaped workpiece therebetween, means operable on one of said first or second elements to so move said elements, a platen on said member, and force-exerting means between said member and platen to force a die carriedby said platen into contact with intermediate portions of a work piece clampedv between said elements.

8. In a stretching press, a frame having a first work-clamping surface, a member slidable on said frame in a first direction toward and from said surface, a bar slidable on said frame toward and from said member and having a second work clamping surface, said member having work clamping surfaces coacting with said first and second surfaces, respectively, power means to slide said bar in said first direction and thereby move said member and all said faces into workclamping relation, a platen guided on said member for movement in a second direction at an angle to said first direction, power means for so moving said platen on said member, and power means for actuating said bar and therethrough said member to move all said faces into workclamping relation.

9. In a stretching press, a frame having a first work-clamping face, a bar movable on said frame and having a second work-clamping face, a member freely movable on said frame between said faces, said member having gripping faces coacting with said first and second faces respectively to grip opposite edges of a workpiece, means moving said bar to force all of said faces into work-clamping position, a platen reciprocable relative to said member and between said faces, and motor means carried by said member connected with said platen and energizable to move said platen to stretch a workpiece clamped by said gripping faces and extending therebetween.

in. A- stretching press c mprisin in c mb nation, a. frame havinggnidesnrfaces determine-- mg a first direction and a first ampin f c -,1 a

h r av g a second cl mping nd s idabl on said surfaces toward andfrorn said first face,

a block member slidable; on said surface and havtween said frame and bar operable to first move said bar into contact with said block and thereafter to move said bar and block to bring said faces into clamping relation, a platen on said block member, and fluid pressure means oper able. to move said platen to stretch a metal sheet clamped between said faces.

11. A- stretching press comprising a press block, a platen, motor means, for effecting relative movement between said block and platen, said block having a pair of clamp faces on opposite sides. thereof, a press frame slidably supporting said block and having a clamp face cooperable with one of the faces on said block, a press bar sli-dable on said frame and having a clamp face cooperable with the other of the clamp faces of said block, motor means for forcing said cooperable clamp faces together to clamp a workpiece therebetween', and cooperating means carried by said frame, bar and block and operable when said clamp faces have been forced together to maintain the said frame, bar and block substantially rigid against the thrust of said: platen on the clamped workpiece.

12. A stretching press comprising a press block, a platen, motor means in said block for actuating said platen, a pair of clamp faces on opposite sides of said block, a press frame slidably supporting said block and having a clamp face cooperable with one face on said block, a press bar slidable on said frame and having a clamp face cooperable with the other of said clamp faces on said block, power means operable to force said cooperable clamp faces together to clamp a work,

piece therebetween, and a plurality of recesses and dowels associated with said block, frame and bar adapted to engage during the clamping operation for guiding said clamp faces together and to maintain said clamp faces rigidly in alignment againstthe thrust of said platen on the workpiece after the clamping operation.

13. In a press, a press block having a central cylinder bore and a plurality of auxiliary bores on each side of said central bore, a plunger reciprocable in each of said bores, a platen, a pivotal connection between said platen and the plunger in said central bore, ways on said platen, slides movable in said ways, pivot means connects ing the ends of each auxiliary plunger with a respective slide, clamp faces on opposite sides of said block, a frame slidably supporting said block, a clamp face on said frame on one side of said block, a movable clamp bar slidable on said frame on the other side of said block, and power means to move said bar against said block and said block against the clamp face on said frame in order to clamp marginal portions of a workpiece extending between said clamp faces, the said workpiece being formed when said platen is actuated upwardly by the plungers connected therewith.

ROBERT J. LINDSEY.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 1,316,211 Wegner Sept. 16,1919 2, 2 ,7 ne --s- S t- 3, 9 3, w s n -.-----,--a, J ne 1 39 40 2,218,503 Brooks Oct. 22, 1940 2,269,549 Oeckl Jan. 13,1942 --r,-.--:--.-r- 2342337 

